Fuse



J. R. FOGAL May 10, 1932.

FUSE

Filed March 4, 1951 2 Sheets-Sheet J. R. FOGAL May 10, 1932.

FUSE

Filed March 4, 1931. 2 Sheets-Sheet Patented May 10, 1932 PATENT crater:

JAY R. FOGAL, OF SAN FRANCISCO, CALIFORNIA FUSE Application filed March 4,

This invention relates to fuses for electrical circuits and has particular reference to novel and unproved fuse constructions which employ ventilating passages for the gases developed by the fuse blowing.

The primary object of the present invention is to provide a fuse construction employing an elongated tortuous passage for the gases, which shall efficiently vent the same from the interior of the fuse and which shall thus cool the gases sufficiently to reduce the fire hazard and also prevent bursting or fracturing the casing surrounding the fuse link.

Another object is to provide a fuse construction of this character which shall consist of few parts that are simple in construction, inexpensive to manufacture, and which are light in weight.

With the foregoing and other objects in view, the invention may be stated to consist in the various novel features of construction and arrangement or combination, all of which will be fully described hereinafter and pointed out in the appended claims.

In the drawings accompanying and forming a part of this application:

Fig. 1 is a view partly in section and partly in elevation of a fuse constructed in accordance with my invention;

Fig. 2is a similar view of a modified form of fuse construction;

Fig. 3 is a plan view of a locking washer used in certain of my fuse constructions;

Fig. 4 is an end elevation of the fuses shown in Figs. 1 and 2;

Figs. 5 and 6 are views partly in elevation and partly in section, each showing a further modification; and,

Fig. 7 is a fragmentary enlarged longitudinal sectional View of a still further modification.

Describing the various parts by reference characters, and referring particularly to Fig. 1, 1 denotes the body portion of the fuse, which in the present instance is in the form of a cylinder of insulating material internally threaded at each end. Secured. to each end of the body portion by the aforementioned threads, is a head 2 which is preferably 5 formed of metal. Each head receives there- 1931. Serial No. 520,130.

in an internally and externally threaded sleeve 3, and a cup shaped member 4. The sleeve 3 in the present instance is formed from sheet metal for economy, and the threads thereon are rolled instead of being cut. The sleeve is of a diameter such that the outer surfaces of the thread contact snugly with the internal surface of the head 2 and thereby form an outer elongated spiral passage 5 between the head and sleeve. Cup shaped member 4 is of a diameter such that it contacts snugly with the internal thread of sleeve 3 and thereby defines an inner elongated spiral passage 6. The end wall of member at preferably extends beyond, and is crimped or rolled over, the outer end of sleeve 3 as indicated at 7, while the side walls of said member are provided with a plurality of apertures 8 adjacent said end wall. By crimping the end wall at 7, a plurality of exhaust passages are provided which establish communication between outer spiral passage 5 and the space between the aforementioned end Wall and a lock washer 12, to be referred to hereinafter.

The fuse illustrated in Fig. 1 is provided with contact blades 10, 10 which project through the end wall of cup members 4 and interconnecting these blades is a fuse link 11 of any suitable or approved design. A look washer 12 embraces each contact blade 10 and a cap 18 is screwed on the head 2 to retain the washer in position. The lock washer, as shown in Fig. 3, is preferably formed of two halves pivoted at 14 and latched at 15 where the recessed ends overlap. This lock washer normally engages suitable shoulders 16 on the knife blade contacts to relieve the fuse link of any strains which might be imposed thereon due to insertion or removal of the fuse from its clips.

WVhen the fuse blows .due to an overload or short circuit, fuse link 11 melts at its weakest portions. This melting of the fuse metal creates a rapid expansion of gases in the fuse body 1 which, if not vented, would rupture the fuse body. In the present instance these gases are expelled at each end of the fuse and first pass through apertures 8 and thence around the inner spiral passage 6,

be reduced to a minimum. It will further be observed that the fuse is of relatively simple construction and a new fuse link may be easily and quickly substituted for one that has been blown.

InFig. 2, I have shown a slightly modified form of fuse wherein the body portion 20 is made of insulating material and externally threaded at each end. An internally and externally threaded sleeve 21 is fitted into each end of the body portion and a cup shaped member 22 is fitted inside of the sleeve; thereby defining an inner spiral passage 23 and an outer spiral passage 24:. The remaining elements of the fuse are similar to those described in connection with Fig. 1 and bear the same reference numerals.

In this modified form of fuse, the gases pass simultaneously through the inner spiral passage 23 and the outer spiral passage. 24 whence they emerge as before,-past the lock washer to the atmosphere.

In Fig. 5 I have illustrated a non-renewable fuse consisting of a body 25 of insulating ma terial which may be pressed or molded to define a rolled thread on the inner and outer surfaces thereof. A cup shaped member 26 is seated in each end of the body portion to define an inner spiral passage 27, and a cap 28 engages over the outer end of the body portion to define an outer spiral passage 29. This cap is preferably fastened to the body as by rivets 30 to prevent unauthorized renewal of the fuse. A fuse link 31' interconnects the end caps 28 and the ends of the link are clamped between the-caps 2 8 and the end wall of the cup shaped members 26.

The gases, in this type fuse pass from the interior of body 25 through inner spiral passages 27, around the outer ends ofthe body portion and then through outer spiral passages 29 to-the atmosphere.

In Fig. 6 the body 33 is formed of insulating material and is internally threaded at each end. The extreme ends of this body portion are serrated as indicated at 34! to provide transverse passages. A cup shaped member 35 is seated in each end of the body in engagement with the internal threads thereof t'o-provide an inner spiral passage 36'. An internally threaded cap 37 is press fitted to each end of the body portion and these threads define an outer spiral passage 38. A

fuse link 39 interconnects the caps 37 and the ends thereof are clamped between said caps and cup shaped members 35. In order to render the fuse non-renewable, and to secure the parts in position, I roll the edge of each cap into a suitable groove in the body portion, and this rolled portion is provided with vent ports 40.

The gases in this type fuse pass through inner spiral passages 36, thence through the transverse ports formed by serrations 34, and through outer spiral passages 38 and ports 40 to the atmosphere.

In Fig. 7, the fuse body is formed of insulating material and is threaded internally and externally at each end portion, and adjacent each end, said body portion is provided with a plurality of transverse ports 51. A sheet metalcup shaped member 52 is seated in each end of the body portion in engagement with the internal threads, thereby defining an inner spiral passage 53. A sheet metal cap 54 is also pressed over each end of the fuse body in engagement with the external threads thereby to define an outer spiral passage 55. If desired, the ends of the caps 54: may be rolled into grooves in the fuse body to retain the caps in position, and these rolled portions are formed with a plurality of ports 56 which connect the outer spiral passage 55 with the atmosphere.

The gases in this type fuse pass out through inner spiral passages 53, thence through ports 51 to outer spiral passage 55 and through ports 56 to the atmosphere.

From the foregoing description, it will be apparent that the fuses described are all constructed of relatively few parts that are inexpensive to manufacture and which when assembled, produce a fuse structure that is exceedingly light in weight so that shipping costs are reduced to a minimum. It will also be apparent that the fuses are so constructed that the gases are materially cooled before they are vented to the atmosphere and hence I.

the fire hazard incident to the blowing of a fuse is reduced to a minimum.

It will be understood that the several features described in connection with the various fuses illustrated may be combined in any desired way. In the smaller size fuses, the contact is usually made with the metal end caps engaging suitable clips while with the larger size fuses, contact is made with knife blades which project from the fuse 31. body as has been described and illustrated in some modifications of my invention.

What I claim is:

1. A. fuse of the character set forth comprising a body portion and a fuse link disposed within said body portion, end contacts carried by said body portion and connected with said fuse link and an internally and externally threaded element associated with one of said contacts and defining inner and outer spiral passages for the escape of gases from the interior of said fuse body to the atmosphere.

2. A fuse of the character set forth comprising a body portion and a fuse link disposed within said body portion, and end con tacts carried by said body portion and connected with said fuse link, the end portions of said fuse being formed with inner and outer spiral passages providing elongated escape passages for the gases in said fuse body.

3. A fuse of the character set forth comprising a body portion and a fuse link disposed within said body portion, end contacts carried by said body portion and connected with said fuse link, internal and external threads associated with each end of said fuse, and means contacting with said threads to define inner and outer spiral passages, said passages communicating with the interior of said fuse body and the atmosphere.

4;. A fuse of the character set forth comprising a body portion and a fuse link disposed within said body portion, the ends of said body portion being threaded internally and externally, and cylindrical elements engaging said internal and external threads to define internal and external spiral passages, said passages communicating with each other and the interior of said fuse body and the mosphere.

5. A fuse of the character set forth comprising a body portion of insulating material, a fuse link disposed within said body portion, the ends of said body portion being internally and externally threaded, a cup shaped member positioned within each end of said body portion and engaging said internal thread to define an inner spiral passage, and a cap closing each outer end of said body portion and engaging said external thread to define an outer spiral passage.

6. A fuse of the character set forth comprising a body portion, an internally and externally threaded sleeve positioned within each end of said body portion, means engaging said threads to define an inner and an outer spiral passage, and a fuse link positioned within said body portion and having contacts at each end thereof.

7 A fuse of the character set forth comprising a body portion, an internally and externally threaded sleeve positioned within each end of said body portion and having the external threads thereof in contact with said body portion to define an outer spiral passage, means engaging said internal threads to define an inner spiral passage, said passages communicating with each other and with the interior of the fuse and the atmosphere, and a fuse link positioned within said body portion and having contacts at each end thereof.

8. A fuse of the character set forth comprising a body portion, an internally and externally threaded sleeve positioned within each end of said body portion and having the external threads thereof in contact with said body portion to define an outer spiral passage, a cylindrical element engaging said internal threads to define an inner spiral passage, said passages communicating with each other and with the interior of the fuse and the atmosphere, and a fuse link positioned within said body portion and having contacts at each end thereof.

9. A fuse of the character set forth comprising a body portion, a head carried by each end of said body portion, an internally and externally threaded sleeve positioned in each head with the external threads thereof in engagement with said head to define an outer spiral passage, a cup shaped member engaging said internal threads to define an inner spiral passage, and a fuse link positioned within said body portion and having contacts at each end thereof.

10. A fuse of the character set forth comprising a body portion, a head carried by each end of said body portion, and internally and externally threaded sleeve positioned in each head with the external threads thereof in engagement with said head to define an outer spiral passage, a cup shaped member engaging said internal threads to define an inner spiral passage, a fuse link positioned within said body portion and having contacts at each end thereof projecting through said cup shaped members, a lock washer surrounding each contact, and a cap engaging each lock washer and connected to said head.

In testimony whereof I aifix my signature.

JAY R. FOGAL. 

